Usually today, or the date of a proposed payout. Rates are published through Dec 31, 2026.

Pick the date range the support was owed over — each month becomes its own amount owing on its due date, the way a court calculates arrears. Enter the amount per month, or the total for the range and we’ll spread it evenly. A lump sum owing adds a one-time amount on a single date.

Add one-time payments on the dates they were actually made, or a payment period for a stretch of regular payments (e.g. $300 per month from one date to another). Payments are applied to arrears first, then amounts owing beyond any order, then the retroactive balance — the full order of priority is outlined at the bottom of the page.

Retroactive support owing without being ordered can attract pre-judgment interest — turn this on to add pre-judgement interest to a retroactive support claim and preview what the court could award. This is not assumed in all cases; once an order fixes the amount, pre-judgment interest no longer applies. With no court order there is no post-judgment interest — no interest accrues unless this is turned on.

Each payment is applied in this order of priority:

1. Arrears — amounts unpaid pursuant to a court order, including required payments toward a retroactive amount that have already come due.
2. Amounts owing beyond any court order.
3. A retroactive amount fixed by an order whose required payments have not yet come due.
4. Anything left over is applied against accrued interest — and past that, carries forward as a credit.

Payments reduce the balance from the day they’re made. Every dollar of arrears bears the same statutory rate, so this is the same as applying payments to the oldest arrears first.